Ultrasound-intensified Leaching of Gold from a Refractory Ore

The effect of ultrasonic energy on the pretreatment and leaching of gold from the refractory ore was investigated. Firstly, the refractory ore was pretreated with sodium hydroxide under ultrasound. Secondly, the pretreated ore was leached under ultrasound. The leaching ratio of gold decreased with increasing of the ultrasound pretreatment time from 1 to 5 h and the NaOH concentration from 5 to 20 wt%. The ultrasound increased remarkably the leaching ratio of gold when the pretreated ore was subjected to ultrasound leaching. The results showed that the appropriate acoustic power was a requirement during the ultrasound-intensified leaching. The leaching ratio of gold increased with an increasing of NaCN concentration from 6 to 18 kg/t. The results demonstrated that the ultrasound is a viable extractive metallurgy technique in pretreatment and leaching for the refractory gold ores.